Although this invention involves a simple change in the function of parts of common machines, this can result in large benefits in energy consumption due to increased efficiency.
In general liquid pumping, the industry is dominated by centrifugal pumps. Although these pumps are xe2x80x9cuser friendlyxe2x80x9d and convenient, they are notoriously inefficient, especially at higher head pressures. Variable displacement positive displacement pumps can be much more efficient. Run as hydroelectric motors, these devices can utilize the potential energy only on demand with very high efficiency and also provide the utilization of low head sources.
The use of these devices as combustion engines could be very productive, especially as automotive engines. An improvement in efficiency in this area can have a large impact on the environment through the reduction of greenhouse gases.
The use of the heat engine as an air cycle Brayton refrigeration system could benefit the ozone layer by replacing organic refrigeration with air.
This invention relates to expansible, chamber positive displacement pumping devices having two elements rotating on different parallel axes and linked together by a third element which is also rotary about it""s own axis. It is a criteria of this in invention that all three elements are dynamnically balanced about each respective axis. This will allow dynamically balanced high speed operation. Generally the three elements are:
A drive shaft -rotor element, an abutment element rotating about a central journal, in a housing and a pivoting element with links the two previous elements together, said pivot element travelling about a circular orbit around the axis of the shaft-rotor element. Several types of pumping devices may be devised using this formula; the devices are: vane pumps and motors of several distinct types, rotating radial piston pumps, rotating pistons in an annular groove, rotating elements in a groove of constant cross section, and rotating rollers in an annular groove. The latter is a simpler pump in that the roller serves both as the second and third element simultaneously so that there is only the shaft-rotor and the roller as moving parts. This is extremely simple pump.
In looking at this invention as compared to existing technology, the primary difference is that the abutments are attached to a hub at the center of the chamber, or constrained to circular motion coaxial with the chamber, whereas in other pumps, such as vane pumps, the abutments move in radial slots in the rotor-shaft element which is a simple geometry, but is flawed in that the vanes are always dynamically out of balance, and the sealing tip of the vanes is always a line contact with the cam chamber wall. By constraining the elements, such as vanes to a circular path about the chamber axis, the vanes need not touch the chamber surface but maintain a parallel tolerance seal at all times. So that the surface is not a cam.
The system is dynamically balanced and may move at higher rotational speeds. The difference here, is that in order to achieve this, the vanes cannot move in radial slots in the rotor but must move in a pivoting motion, not perpendicular to the axis of the rotor, but perpendicular to the chamber. Thus vanes, pistons, or rollers must move with circular motion which is not about the axis of the rotor, but about the axis of the chamber, This produces the precise motion but also requires the pivoting link. Generally, the pivoting link moves at a constant angular velocity with the rotor but with a changing radial distance from the axis of the rotor. With respect to the central journal, the pivot element travels at a constant radial distance from the axis of the journal, but with changing angular velocity. This geometry allows a very simple method of obtaining variable displacement. Two housing elements are fastened with the ability to slide, having one housing have shaft rotor, the other have the chamber with central journal so that as the axes are displaced, the displacement changes. This is especially valuable for increased performance and efficiency in the pumping of liquids.
The concept works for rotating radial piston technology. In this case, the pistons are always rotating about the central hub at a fixed radius but also rotating at a constant angular velocity with the rotor, again with the pivot link required. The pivot link becomes the cylinder in which the piston moves, the pivot link orbiting the rotor shaft axis, and the piston orbiting the central hub journal. In the pumping of liquids, this may allow the fluid to act directly upon rotor and hub and take almost all pressure load off the piston or pivot cylinder. Further, the device again may be variable displacement, this time by only shifting the axis of central hub. As a further benefit, the system is very simply rotary ported on the periphery of the rotor and can very simply be pressure balanced.
As a pneumatic device, the system has benefits over reciprocating technology which has two operational boundaries. The lower rpm boundary is the leakage which decreases linearly with increasing rotational speed. In this, the two technologies are equivalent. The second boundary of reciprocating engines is caused by F=ma, or that the weight of the parts increase with rotational velocity so as to cause increased friction and wear and loss of efficiency and power. In this case, the two technologies are not equivalent.
Provided each element (shaft-rotor, pistons, pivot cylinder) are dynamically balanced (about their own axis of rotation), there are no increased forces caused by increased rotational velocity. What this means is that this device becomes increasingly efficient (less leakage) with velocity rather tan less efficient. A third factor is that increased velocity causes aspiration problems in reciprocating devices due to valves springs and also size of valves not allowing air flow at velocity. In this technology, no valves are required either for intake or discharge. In the case of use as a heat engine, the device may run as a two cycle but is probably better as a four cycle, as the expansion volume may be made larger that the compression volume for higher efficiency. In this case, the compression chamber must transfer the gas into the expansion chamber through either a rotary valve or through a mechanical valve run off the center hub. Also an injector may be operated in the same way. The compression piston and expansion piston may be one part on the journal, and also include the valve and injector in the same part, and the pivot cylinder may have both compression and expansion in the same part. Thus a very simple engine can be rotor-shaft having a single pivot cylinder, and a single piston element rotating upon center journal I, and having simply open rotary ports. Thus the whole engine consists of three moving parts plus a housing. Furthermore, the center of the device constitutes a liquid pump between piston and rotor so as to accomplish both lubrication and cooling. This pumping zone may have duplex ports so that one port is pumping cooling fluid but as the chamber becomes small, the port closes and it pumps high pressure lubrication to the bearing surfaces.
In conclusion, this technology is similar and parallel with other existing technologies, but it is a simpler and more efficient way to accomplish the work, either in liquid pumping or in pneumatic applications. It can be applied to extremely wide range of products. It can also open some new doors to advanced systems, especially in fluid power transmission and also in energy conversion.
Having designed patented and built many expansible chamber pumps, it came to my attention that although my fixed displacement pumps were efficient, when load varied, the drive motor suffered in efficiency. Thus my objective was to invent a pressure regulated expansible chamber pump which would raise the efficiency of the combined pump and drive motor system. The objective was to encompass general water pumping as well as fluid power. A logical staring point was the examination of variable displacement pumps, such as axial piston pumps and single lobe vane pumps. Vane pumps appeared to have promise but had some serious drawbacks. These drawbacks were overcome by changing the manner in which the vanes operated. By pivoting the vanes from the axis of the chamber, sealing and wear problems are dismissed. To do this precluded using vanes in radial slots in the rotor. It was evident that a new criteria had to be introduced which involved a pivoting link between vanes and the driving rotor. Following this line of inquiry led to use of a similar approach for pistons and roller abutments. Because both sealing and dynamic balance was greatly improved, high rotational speeds became possible which seemed an excellent combination for pneumatic applications. Further design in both piston and vanes for pneumatic devices, including combustion engines showed promise. These designs appear to allow a much greater swept volume for size and also a much greater operating range, resulting in higher performance and efficiency.
A first liquid pump model was built which confirmed the following: variable over center (and reversible) displacement, high displacement for size, excellent sealing of chambers, precise orbits of vanes allowing pump to start pumping from stall (rather then having to rely on centrifugal force on vanes), excellent porting allowing high flow rates, smooth silent pulse free operation, no vibration indicating dynamic balance. This model confirmed most of the anticipated benefits as proof of concept. The successive designs were extensions of the basic ideas put to various industrial uses including engines.
Vane pumps are in common use in industry. This vane pump design relates most closely to vane pumps with a circular chamber rather than balanced (double) pumps. It relates to variable displacement as well as fixed displacement pumps. The main feature of this invention is that the vanes are pivoted from the axis of the circular chamber. The closet art found was a patent by Charles A Christy U.S. Pat. No. 4,073,608, Feb. 14, 1978 reference 418/241,253 in which vanes are pivoted from the center axis of the chamber and passed through pivoting vanes in a rotor and ported as a liquid pump. In Mr Christy""s pump, the vanes are pivoted upon a stationary protruding journal. While the pump can be made to operate in this manner, in order to reduce wear and increase operational speed, hence performance and efficiency, the vanes must pivot about a shaft which is an idler shaft, rotating at the same essential speed as the drive shaft. Thus, the surface speed seen by Mr. Christy""s vane to journal surface are about an order of magnitude greater, Mr. Christy has shown his invention as a fixed displacement liquid pump. I felt that my other design, without rotor, to be more suitable for liquid pumping. The design with rotor is more suitable for pneumatics, in large due to the availability of an internal pump for liquid which may cool, lubricate, and seal the device. Mr. Christy specifically states that this zone must be relieved to avoid pumping, probably because he only envisioned a liquid pump. As a liquid pump, the inner chambers are doing the opposite as the outer chambers. While the outer is in suction, the inner is inner discharge; obviously not ideal. Also, the pump of Christy will not handle particulate matter due to the proximity of rotor and stator in the seal zone. Nor is Mr. Christy""s pump variable displacement.
In using this technology for fluid power as in vane pump 3 or piston pump 17, I quote from Industrial Fluid Power Hodges Womack, Vol 1 page 18 discussing variable displacement single lobe pumps, xe2x80x9cDue to the unbalanced nature of single, they are more limited in both pressure and flow than the balanced, double acting pumps to be described later. For example, maximum ratings on the pump illustrated is 21 GPM at a shaft speed of 1750, and with a pressure limitation of 1500 psi. High speed and/or high pressure will produce excessive vibrationxe2x80x9d. And, on Page 183, xe2x80x9cbalanced vane pumps due to mechanical construction cannot be built to have variable displacementxe2x80x9d. In comparing the variable vane, piston, or roller pumps of this technology, we see that these pumps can have high speeds, high flow and do not have excessive vibration. Further, if we change vanes for pistons as in FIG. 17 we have a variable displacement balanced pump which has a much greater capacity than either the existing vane or piston pumps. Thus, this appears to be an extension of the fluid power technology.
In comparing the piston technology with existing reciprocating engines, we see that the basic elements are similar, however, and the basic function of compressing air, introducing fuel, and expanding is similar, however the manner in which these elements perform these functions is quite different. In the case of reciprocating technology, the pistons are driven by connecting rods by a crank shaft, obtaining reciprocating motion. The connecting rod produces side loads on the piston. In the rotary engine, the pistons are journalled to the central hub with no side loads. In the reciprocating engine, as rotational speeds increase, the pistons and connecting are subject to very high accelerations resulting in wear and friction and power loss, thus curtailing the operating range significantly and unfortunately, the curtailed portion is theoretically the most efficient portion due to less leakage.
In comparing the vane engine, again the expected curves are similar and the engine may operate on a significantly more efficient zone of the curve. These engines are significantly smaller in size for output than reciprocating devices. The rotary vane engine with divided chambers (larger expansion) allows continual open intake and exhaust ports which are very large. This is significantly better than reciprocating devices. While pistons or vanes are not subject to excessive force due to acceleration, they are subject to centrifugal force. This can be balanced by counterweights on the hinge. The same is true for the swivel elements.
1. A first object is to provide a vane device in which the vanes are able to provide tolerance seating and thus avoid friction and wear.
2. A second object is to provide a liquid pump which is able to pump fluids with debris (trash pump).
3. A third object is to provide a liquid pumpxe2x80x94motor which has variable displacement.
4. A fourth object is to provide a liquid pumpxe2x80x94motor in which the pressure head regulates the flow.
5. A fifth object is to provide a pumpxe2x80x94motor which is variable over center and reversible.
6. A sixth object is to provide a fluid motor in which the pressure load may increase or decrease the displacement, hence flow and cause the power to increase or decrease with the demand.
7. A seventh object is to provide a vane pump with vanes adjustable for wear and tolerance.
8. An eight object is to provide a vane pump with a flexible diaphragm material attached to and joining vanes.
9. A ninth objects is to provide a fixed displacement liquid vane pump in which the rotor provides a seal with the chamber as well as the seal between vanes.
10. An tenth objects is to provide an expansible chamber vane pneumatic device with improved sealing.
11. A eleventh object is to provide such a device with an internal liquid pump for cooling, lubrication and sealing.
12. A twelfth object is to provide a variable compression ratio compressor or expander.
13. An thirteenth object is to provide such a device as two stroke engine.
14. An fourteenth object is to provide two vane devices, linked together by gears or other as a heat engine of Brayton Cycle or Otto Cycle or refrigeration device compresses into a chamber where heat is either added or subtracted, and the working fluid is then expanded through the other vane device which is linked to the first one by gearing.
15. An fifteenth object to provide a pneumatic device with hinged pistons in which there are no accelerations on the pistons and thus the device does not have the curtailment of it""s operating curve due to increasing weight of reciprocating parts and thus be more powerful and more efficient.
16. An sixteenth object to provide such as engine or compressor in which valves are simple and rotary.
17. An seventeenth object to provide such as engine having only 10% approximately of the parts of a conventional engine.
18. An eighteenth object to provide a heat engine in which the expansion volume is greater than compression volume.
19. An nineteenth object to provide a rotary hinged piston four cycle engine.
20. An twentieth object to provide such an engine to be able to function as Otto cycle, Diesel cycle, or Brayton cycle or other cycle variations.
21. An twenty first object to provide a more efficient engine due it higher rotational speeds, said engine having all moving parts in dynamic balance.
22. A twenty third object to provide a variable radial piston pump which is pressure balanced and having greatly reduced bearing requirements than other piston pumps.
A first embodiment has the advantage of simplicity and economy while providing a sophisticated pump or motor of the expansible chamber type which can be manually variable, displacement, reversible, or can be pressure regulated. In the second embodiment, the elements are free cylindrical rollers, and wear takes place over a large surface area rather than on a line contact In the roller device, the radius of the center bushing plus the diameter of the roller equals the outer radius of the chamber. Any wear, even if it is on 4 rollers, can be adjusted by replacing the single bushing. A major advantage in this device is cost because the parts are very simple. This allows the slots to be radial in the rotor. Likewise, vanes may be the pivot elements provided the circular tips and are of sufficient width so that the contacts are always perpendicular to the chamber wall.
Another advantage is that the device can be very simply made variable displacement by only moving the two housing surfaces (which have mating planar surfaces) relative to each other and thus changing the relationship between axis of chamber cavity to axis of shaft and rotor rotation.
An advantage of the vane embodiment is that it can form a double pump. If the rotor annular ring divides the chamber. This is most useful as a vane motor in which there are two sets of intake and discharge ports. By choosing the inside chamber ports only, the displacement is lower, the rotational speed higher; by using the two ports on the outside chamber only (and bypassing the inner pumping chamber), the device has medium displacement and a medium rotational speed, by using all ports valved together, the device has higher displacement and lower speed. Thus, it has three ranges from low torque high speed to high torque low speed.
The main advantage gained by pivoting vanes on the chamber axis is a reduction in wear and friction and a positive system that doesn""t rely on centrifugal for or pressure loading to insure vane to case sealing. Another advantage is in porting, where the ports can be wide open rather than as slotted ramps.
Since the ports are wide and open, in a preferred embodiment for liquid pumps there is no rotor with in the working chamber. This allows the working chambers to be large and clean of obstruction and allows a large cavity in which debris can be pumped. Further, the vanes pass the ports at right angles and there is no wedge tolerance as between rotor and chamber in which to catch debris and score the parts.
By allowing the part with chamber and hinge journal to be able to be moveable with respect to the shaft axis, then variable displacement occurs. The two axes are always parallel but can vary in distance apart. Variable displacement allows better performance and higher efficiency.
By providing the pressure output on one side of the moveable chamber and a return mechanism, such as a spring opposing said motion, the pumping device may be pressure controlled and made to provide a constant torque device despite head pressure. Such a device can have a much higher efficiency than a centrifugal pump which has much the same, (nearly constant drive torque).
If the moveable chamber can shift over center, then the pump becomes variable and also reversible, This can be valuable in power transmission or in cases where one wants to alternately provide a pressured fluid and then suck out the fluid. Also, returning to center, the device simply rotates but does not pump and has the advantage of a neutral position. If the moveable chamber is positioned at an initial displacement and spring provided on either side which can be adjusted to the initial displacement, the pressure may be applied on either side. If the pressure is applied and to decrease displacement. Then it is as previously discussed, a torque restricting device. On the other hand, if the pressure is applied in the opposite side, it causes the displacement, hence torque to increase, and hence power to increase. This is an ideal configuration for hydropower, or for fluid power where driving a generator with varying electrical loads, thus varying torque requirements. The advantage of this is that elaborate control mechanisms are eliminated. A further advantage is that the pressure fluid, a potential energy source, has been conserved as it is only used upon demand.
Another advantage is that as a fluid motor, the vane device can start from stall, unlike vane devices with vanes held out by centrifugal force and require a fairly high rotational speed before starting to pump
Another embodiment provides a rotor with pivoting slots holding the vanes and the rotor is aligned in a dished out portion of the pump this be satisfactory for lubricating fluids but will probably have little advantage over the previous embodiment, however, on the other hand, using this configuration in pneumatic applications has advantages in sealing and porting.
Having the vanes travel with circular motion off a central shaft provides excellent sealing with out extreme friction. Porting through the dished out portion of the chamber allows excellent rotary porting. Allowing the central pumping chamber inside the rotor ring to pump a lubricating fluid provides a heat sink, lubrication of vanes and sealing of sliding surfaces. This allows high speed operation, less slippage, higher efficiency.
Using this concept seems to have advantages in terms of building internal combustion engines. The tolerance seal vanes approximate piston and cylinder in having parallel surfaces and with the higher speeds available with the vane device means that sealing rings may not be required due to shorter leakage time. The central lubrication and cooling pump being built in is definitely an advantage. Having the sealed zone in the dished out portion has advantages for combustion. Due to large displacement and high speed operation the power to weight ration is excellent. The device is very simple and would eliminate most parts.
By linking two vane devices together and having them share a common chamber, a Brayton cycle may be used, either as a positive displacement heat engine or as a cooling system such as an air cycle refrigeration. System compression volume may be different than the expansion volume, allowing higher efficiency. Environmentally, there are large advantages due to lower pressure combustion not producing harmful emissions and long expansion providing better efficiency and loss noise.
Similarly, an Otto Cycle or Diesel 4 stroke engine of this configuration would have many of the same advantages, sealing, cooling, different compression ratio than expansion ratio. This will have the advantage of more efficiency, less power loss due to blow down and be quieter.
There are several very important advantages of the rotating piston engine embodiment over existing reciprocating devices. The main advantage is that this device does not lose the efficiency at higher rotational speeds as does a reciprocating engine. This allows the engine become increasingly efficient with increased rotational speed due to reduced leakage per cycle.
Another major advantage is that the device is much simpler and eliminates most of the parts of a reciprocating engine,
Another advantage is that this engine may have larger expansion than compression resulting in better efficiency, quieter operation, less heat loss.
Another advantage is that the engine may be operated on a number of cycles. Otto, Diesel, Brayton and also external combustion.
Another advantage is that as a Brayton, it may be run as an air cycle refrigeration device by having the combustion heat chamber instead be a heat sink.